scholarly journals The synthesis of polyhydroxyalkanoates from low carbon wastewater under anaerobic-microaerobic process: effects of pH and nitrogen and phosphorus limitation

2021 ◽  
Vol 27 (6) ◽  
pp. 210467-0
Author(s):  
Kequan Zhang ◽  
Qian Fang ◽  
Yihan Xie ◽  
Yujia Chen ◽  
Tong Wei ◽  
...  
Keyword(s):  
Weight Ratio ◽  
Phosphorus Limitation ◽  
Nutrient Restriction ◽  
Low Carbon ◽  
Nitrogen And Phosphorus ◽  
Dry Cell Weight ◽  
Process Effects ◽  
Effects Of Ph ◽  
New Type ◽  
Dry Cell

Polyhydroxyalkanoate (PHA) is a new type of bio-polyester which is expected to replace traditional petroleum-based plastics. The experiment was carried out based on anaerobic-microaerobic process. Firstly, the PHA accumulation capacity of activated sludge under different pH conditions was discussed, and then the batch test of nitrogen and phosphorus limitation was carried out under the condition of optimal pH. Moreover, the content of PHA monomer under nutrient restriction was also studied. The experimental results showed that when pH was not controlled (7.5~8.5), C:N and C:P weight ratio was equal to 150, the maximum content of PHA accounted for 50.39% and 36.07% of the dry cell weight, respectively. Besides, it was found that increasing the C:N weight ratio was beneficial to increasing the proportion of polyhydroxyvalerate (PHV) monomer in PHA.

The Recovery and Synthesis of Polyhydroxyalkanoates in the Process of Nitrogen and Phosphorus Removal in Low-Carbon Sewage Based on pH and Nitrogen and Phosphorus Restriction Under Anaerobic-Oxygen Limited Process

2021 ◽  
Author(s):  
Kequan Zhang ◽  
Qian Fang ◽  
Yihan Xie ◽  
Yujia Chen ◽  
Tong Wei ◽  
...  
Keyword(s):  
Carbon Source ◽  
Phosphorus Removal ◽  
Ph Value ◽  
Source Control ◽  
Low Carbon ◽  
Nitrogen And Phosphorus ◽  
Nitrogen And Phosphorus Removal ◽  
Urban Sewage ◽  
Dry Cell Weight ◽  
Limited Process

Abstract Polyhydroxyalkanoate (PHA) is a new type of bio-polyester which is expected to replace traditional petroleum-based plastics. It is also a critical transformation hub of carbon source in nitrogen and phosphorus removal in sewage. Based on the anaerobic-oxygen limited process, the experiment took organic solid waste fermentation liquid as carbon source control hub and realized PHA synthesis and recovery in denitrification and phosphorus removal from low carbon sewage the SBR reactor by regulating pH value and nitrogen and phosphorus restriction. The experimental results showed that when the ratio of C/N and C/P was 150, the content of PHA accounted for 50.39% and 36.07 of the dry cell weight, respectively. Besides, it was found that increasing the C/N ratio was beneficial to increasing the proportion of PHV in PHA. This study proved the feasibility of using an anaerobic-oxygen limited process to recover PHA in nitrogen and phosphorus removal from low-carbon sewage, which saves gas and reduces energy consumption. At the same time, it also provides some help for the follow-up study of low-carbon urban sewage nitrogen and phosphorus removal coupled with resource recovery of PHA to guide the water industry economy to develop in a circular and sustainable direction

scholarly journals Complete biosynthesis of a sulfated chondroitin in Escherichia coli

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Abinaya Badri ◽  
Asher Williams ◽  
Adeola Awofiranye ◽  
Payel Datta ◽  
Ke Xia ◽  
...  
Keyword(s):  
Chondroitin Sulfate ◽  
Scale Up ◽  
Production Methods ◽  
E Coli ◽  
Microbial Cell Factories ◽  
Cell Factories ◽  
Microbial Product ◽  
Dry Cell Weight ◽  
One Step ◽  
Dry Cell

AbstractSulfated glycosaminoglycans (GAGs) are a class of important biologics that are currently manufactured by extraction from animal tissues. Although such methods are unsustainable and prone to contamination, animal-free production methods have not emerged as competitive alternatives due to complexities in scale-up, requirement for multiple stages and cost of co-factors and purification. Here, we demonstrate the development of single microbial cell factories capable of complete, one-step biosynthesis of chondroitin sulfate (CS), a type of GAG. We engineer E. coli to produce all three required components for CS production–chondroitin, sulfate donor and sulfotransferase. In this way, we achieve intracellular CS production of ~27 μg/g dry-cell-weight with about 96% of the disaccharides sulfated. We further explore four different factors that can affect the sulfation levels of this microbial product. Overall, this is a demonstration of simple, one-step microbial production of a sulfated GAG and marks an important step in the animal-free production of these molecules.

scholarly journals Optimisation of Recombinant Myrosinase Production in Pichia pastoris

2021 ◽  
Vol 22 (7) ◽  
pp. 3677
Author(s):  
Zuzana Rosenbergová ◽  
Kristína Kántorová ◽  
Martin Šimkovič ◽  
Albert Breier ◽  
Martin Rebroš
Keyword(s):  
Pichia Pastoris ◽  
Plant Defence ◽  
Plant Secondary Metabolites ◽  
Specific Productivity ◽  
Fermentation Conditions ◽  
Threefold Increase ◽  
Dry Cell Weight ◽  
First Time ◽  
Hydrolysis Of ◽  
Dry Cell

Myrosinase is a plant defence enzyme catalysing the hydrolysis of glucosinolates, a group of plant secondary metabolites, to a range of volatile compounds. One of the products, isothiocyanates, proved to have neuroprotective and chemo-preventive properties, making myrosinase a pharmaceutically interesting enzyme. In this work, extracellular expression of TGG1 myrosinase from Arabidopsis thaliana in the Pichia pastoris KM71H (MutS) strain was upscaled to a 3 L laboratory fermenter for the first time. Fermentation conditions (temperature and pH) were optimised, which resulted in a threefold increase in myrosinase productivity compared to unoptimised fermentation conditions. Dry cell weight increased 1.5-fold, reaching 100.5 g/L without additional glycerol feeding. Overall, a specific productivity of 4.1 U/Lmedium/h was achieved, which was 102.5-fold higher compared to flask cultivations.

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